const arr = []
const arr2 = new Array(5).fill(new Array(5).fill(0))

for (let i = 0; i < arr2.length; i++) {  // 2
    for (let j = 0; j < arr2[i].length; j++) {  // 1
        if (i === 0 && j === 0) {
            arr2[i][j] = 1
        }
    }
}

console.log(arr2)

